An operating system (OS) is a set of programs that manage computer hardware resources and provide common services for application software. For hardware functions such as input and output and memory allocation, the operating system typically acts as an intermediary between application programs and hardware. Operating systems may be found on a variety of devices, including desktop computers, servers, smartphones, video game consoles, and so forth.
A virtual machine (VM) is a portion of software that, when executed on appropriate hardware, creates an environment allowing the virtualization of an actual physical computer system (e.g., a server, a mainframe computer, etc.). The actual physical computer system is typically referred to as a “host machine,” and the operating system of the host machine is typically referred to as the “host operating system.”
A virtual machine may function as a self-contained platform, executing its own “guest” operating system and software applications. Typically, software on the host machine known as a “hypervisor” (or a “virtual machine monitor”) manages the execution of one or more virtual machines, providing a variety of functions such as virtualizing and allocating resources, context switching among virtual machines, etc.
The Advanced Configuration and Power Interface (ACPI) specification provides an open standard for device configuration and power management by the operating system. The ACPI specification defines four global “Gx” states G0 through G3, six sleep “Sx” states S0 through S5, four device states D0 through D3, four processor states C0 through C3, and up to 17 implementation-dependent power-performance states P0 through Pn, where n is an integer between 1 and 16 inclusive. In addition, ACPI defines several tables that provide an interface between an ACPI-compliant operating system and system firmware, including a Differentiated System Description Table (DSDT), a Secondary System Description Table (SSDT), and a System Resource Affinity Table (SRAT).
Each ACPI table may be represented by a string of symbols. A compiler may be used to process the string of symbols and generate a binary associated with the ACPI table.